WCDMA Uplink Power Offset for Base Station Acknowledgment
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Solution Overview
Problem
In 3rd generation wireless communication systems like WCDMA and OFDM, uplink communications face challenges due to power limitations at the radio base station, particularly when handling acknowledgments for multiple users in difficult radio conditions, leading to increased power consumption and potential delays in data transmission.
Innovation Solution
Mobile terminals receive configuration messages with power offset and maximum retransmission parameters, allowing them to adjust transmission power and number of attempts for non-scheduled transmissions, while the network prioritizes and adjusts power settings for acknowledgment messages, including the option to drop or reduce power for ACK/NACK signals based on available power and user service class.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radio base station transmits acknowledgments to multiple users in difficult radio conditions simultaneously, then the system reliability is improved, but the power consumption increases significantly
Solution Approach 1:
The patent changes the power parameter dynamically by introducing a power offset value that adjusts the transmission power for acknowledgment messages based on the number of users requiring acknowledgments. When multiple users are in difficult radio conditions, the power offset is adjusted to prevent excessive power consumption while maintaining necessary reliability.
Solution Approach 2:
The patent makes the acknowledgment transmission dynamic by allowing the radio base station to adaptively adjust transmission parameters including power levels and timing based on current system conditions. The power offset parameter is dynamically modified according to the number of users requiring acknowledgments, enabling the system to respond to changing traffic conditions.
2Reliability
If the mobile terminal transmits with higher power to ensure reliable reception, then the transmission reliability is improved, but the power availability at the terminal is exhausted faster
Solution Approach 1:
The patent applies parameter changes by allowing the mobile terminal to adjust its transmission power based on the power offset parameter received from the network. This enables the terminal to transmit at appropriate power levels without exceeding available power, balancing reliability with power conservation.
3Productivity
If the Node-B sets a high upper limit on transmission power for user equipment, then the data rate potential is increased, but the user equipment may not have sufficient power to transmit even a single Protocol Data Unit
Solution Approach 1:
The patent resolves this contradiction by introducing a power offset parameter that adjusts the effective transmission power limit based on current conditions. The Node-B configures an upper limit, but the actual transmission power is modified by the power offset, ensuring that user equipment transmits at feasible power levels while still allowing for high data rates when power is available.
4Quantity of substance
If the system targets a larger number of transmission attempts for each data entity, then the system capacity is increased, but the transmission delays increase
Solution Approach 1:
The patent applies dynamics by enabling adaptive transmission strategies where the system can adjust the number of transmission attempts and power levels based on current conditions. Hybrid ARQ with soft combining allows the receiver to accumulate received energy across multiple attempts, effectively increasing capacity while managing delays through intelligent combining rather than simple retransmission.
Data Source
AI summary
Methods for improving uplink communications in a Wideband Code Division Multiple Access (WCDMA) communication system, wherein mobile terminals can transmit at various transmission power levels. In a mobile terminal, the method includes the steps of receiving a configuration message having at least one of a power offset parameter and a maximum number of retransmission attempts parameter; when the mobile terminal performs a non-scheduled transmission, it transmits according to the parameters contained in the configuration message. In a network node, the method includes the steps of transmitting to at least one mobile terminal the configuration message having at least one of a power offset parameter and a maximum number of retransmission attempts parameter; and, adjusting a power setting for the transmission of acknowledgement or negative-acknowledgement messages from the wireless network to one or more of mobile terminals.